One Category, One Solution
Silverfish, earwigs, house centipedes, crickets, pillbugs, and the fall wave of stink bugs, boxelder bugs, and cluster flies are grouped together by pest professionals as occasional invaders, and the label is useful because it tells you how to deal with all of them at once. Unlike roaches or bed bugs, these are not pests that establish a breeding population inside your home. They live outdoors and wander in, usually seeking moisture, sometimes seeking shelter from heat or cold, and they turn up in basements, bathrooms, and along foundations rather than infesting the way true indoor pests do.
That shared behavior means they share a solution. Because they come in from outside in search of moisture and shelter, the way to get rid of them, and keep them out, is to make the home dry and sealed rather than to chase each species with a different product. Reduce the dampness that draws them, close the gaps they enter through, and remove the outdoor harborage right against the house, and the whole category drops off together.
It also helps to know that most occasional invaders are harmless, more startling than dangerous. Silverfish can damage paper and stored goods, and a heavy cricket or centipede presence is unpleasant, but these are nuisance and comfort pests, not health threats. That lowers the urgency, but the persistent ones are still worth solving, and the fix is refreshingly consistent across the group.
The Usual Cast of Occasional Invaders
Different bugs, same story, each wandering in from outside for moisture or shelter.
Small, silver, teardrop-shaped, and fast, favoring dark, humid spots, bathrooms, basements, and closets. They feed on starches and can damage paper, books, and stored fabrics.
Dark, with distinctive rear pincers. They shelter in damp mulch, leaf litter, and under objects outdoors and wander in during hot or dry spells. The pincers look alarming but are essentially harmless.
Fast, many-legged, and unnerving, they hunt other insects in damp basements and bathrooms. A sign of both moisture and a supply of smaller prey pests to feed on.
Field and camel crickets enter basements, garages, and crawlspaces seeking shelter, especially as weather shifts. Loud and, in numbers, capable of damaging fabrics and paper.
The "roly-polies," moisture-dependent creatures that live in damp soil and mulch and wander into ground-level spaces. Harmless and a clear indicator of excess moisture.
Stink bugs, boxelder bugs, cluster flies, and lady beetles that mass on warm walls in autumn and slip inside to overwinter, then reappear indoors on warm days. Covered in depth in our winter guide.
Moisture and Entry: the Two Levers
Because occasional invaders are drawn indoors by dampness and enter through gaps, two controls handle nearly the entire category. The first is reducing moisture, both the humidity these pests seek and the damp harborage that sustains them. Running dehumidifiers in basements and crawlspaces, fixing leaks and drips, improving ventilation in bathrooms, and correcting drainage so water does not pool against the foundation together remove the single biggest attractant. Silverfish, centipedes, pillbugs, and earwigs cannot thrive in a dry environment.
The second is exclusion, sealing the ways in. Weather-strip doors, add door sweeps, caulk gaps around windows and utility penetrations, and screen vents to close the entry routes these wanderers use. Because they are coming from outside rather than breeding within, a well-sealed home keeps the great majority out, which is why exclusion is even more central for occasional invaders than for many other pests.
The third, supporting move is managing the exterior harborage right against the house, pulling mulch and leaf litter back from the foundation, moving woodpiles away, and trimming dense vegetation, since that damp perimeter zone is where these pests gather before they come in. Our occasional invader control pairs a treated exterior barrier with this moisture-and-exclusion approach.
Clearing Occasional Invaders
Quick Answers by Pest
The universal fix is moisture plus exclusion, but a few pest-specific notes help.
Target humidity above all, they cannot survive dry conditions, and protect paper and fabrics in sealed containers. A dehumidifier is often the single most effective step.
Focus on the exterior: reduce mulch and damp debris against the house, since earwigs invade from that perimeter harborage, usually during heat or drought.
They are hunting other bugs, so reducing the smaller pests they eat, and the moisture both need, removes their food supply and their reason to stay.
Seal garage and basement entry points and reduce clutter; exterior lighting also draws them, so managing lights near doors helps.
Purely a moisture signal, correct damp soil and drainage against the foundation and they disappear, as they cannot survive indoors for long.
Exclusion done in late summer and fall is the key, sealing them out before they enter, plus vacuuming the ones that get in. See our winter guide for the full approach.
When an Invasion Signals Something Bigger
Because occasional invaders are a symptom of conditions rather than a self-sustaining infestation, a heavy or persistent presence is worth reading as a signal. A basement full of silverfish, centipedes, and pillbugs is really telling you the space is too damp, and that underlying moisture can matter for the house itself, not just the bugs, contributing to mold, wood decay, and a hospitable environment for other pests. Solving the invaders and solving the moisture are often the same project.
That is where a professional adds value beyond the pests themselves: identifying the moisture and entry issues driving repeated invasions, treating the exterior barrier and harborage effectively, and, for the fall overwintering pests, timing exclusion before the seasonal push. If you are dealing with recurring waves of occasional invaders despite basic efforts, it usually points to a moisture or sealing problem worth diagnosing, and fixing it resolves both the nuisance and its cause.
Occasional Invader Questions
What are occasional invaders?
It is the pest-industry term for outdoor pests that wander into homes seeking moisture or shelter without establishing an indoor breeding population, silverfish, earwigs, centipedes, crickets, pillbugs, and the fall overwintering bugs like stink bugs and boxelder bugs. Because they share that behavior, they also share a solution: moisture control and exclusion.
Are silverfish and centipedes dangerous?
No. They are nuisance pests, not health threats. Silverfish can damage paper, books, and stored fabrics, and a heavy presence of any of these is unpleasant, but they do not bite meaningfully, spread disease, or harm the home structurally. The main reason to control them is comfort and protecting stored goods.
Why do I keep getting silverfish or bugs in my bathroom or basement?
Almost always moisture. These pests are drawn to and sustained by humidity and dampness, so a persistent presence in bathrooms, basements, and crawlspaces points to excess moisture there. Reducing humidity with ventilation and a dehumidifier, and fixing any leaks, is usually what finally clears them.
How do I keep occasional invaders out for good?
Make the home dry and sealed. Reduce indoor humidity, fix leaks and drainage, seal entry points with weather stripping and caulk, declutter damp storage areas, and pull mulch and debris back from the foundation. Because these pests come from outside, a dry, well-sealed home keeps the whole category out far better than treating them one by one indoors.
Recurring Invaders in the Basement or Bath?
Waves of silverfish, centipedes, or crickets usually mean a moisture and sealing problem worth diagnosing. Tell us what you are seeing and we will schedule a free inspection that addresses both the pests and their cause.
Schedule Your Free InspectionAbout LegendaryWays Pest Control
LegendaryWays Pest Control is an award-winning, locally owned company with over 20 years of experience protecting homes and businesses nationwide. These guides are written by the technicians who do the work, not a content mill, so the advice reflects what actually solves the problem in the field. When a pest problem is past the DIY stage, our free inspection carries no obligation, and every plan is month-to-month with free re-service between visits.
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